Abstrakt
V-Rh(111) bimetallic systems were prepared by deposition of 0.4 and 2.5 ML of vanadium on Rh(111) surface at 823 K and by annealing up to 1023 K. Subsurface alloys of similar composition and electronic structure were formed.
On the latter one, (2 x 2) surface reconstruction was observed. Electronic structure of the V-Rh(111) subsurface alloys was studied by photoelectron spectroscopy utilizing synchrotron radiation.
Atomic structure was studied by means of LEED and X-ray photoelectron diffraction. Chemisorption properties were probed by CO and O-2 adsorption.
The topmost atomic layer with (2 x 2) reconstruction consisted exclusively of Rh atoms. The obtained results indicate formation of alloy with Rh3V composition and L1(2)-type structure.
Changes observed in the electronic structure were correlated with lower reactivity towards CO adsorption. The photoemission data indicate that the CO saturation coverage at 300 K is reduced to less than half on the alloy surface as compared to clean Rh(111).
Oxygen adsorbed on the alloy surface strongly interacted with the subsurface vanadium and induced formation of a surface vanadium oxide. (C) 2012 Elsevier B.V. All rights reserved.